My Firestudio 2626 synced immediately to my Yosemite upgrade. I am still using the Universal Control 1.2 app, but I have already done several sessions with Logic 9 over the past few days and have not experienced any issues at all.

Not sure if that will be the situation for everyone, but my FS is perfectly happy on OS X 10.10.

I have not upgraded yet to Yosemite, but i have been using my FS 2626 under 10.9 Mavericks with Logic X for a while now with no issues to speak of. A pleasant surprise indeed. i'll have to give Yosemite a try soon.Kevin WhittenburgFirestudio 2626Mac OS X 10.6.8 and 10.9Logic Pro 9 and Logic Pro X, Cubase 7.58 core Mac Pro early 2009 - 20 GB RAM

kevinwhittenburg wroteI have not upgraded yet to Yosemite, but i have been using my FS 2626 under 10.9.5 Mavericks with Logic X 10.2.2 for a while now with no issues to speak of. A pleasant surprise indeed. I'll have to give Yosemite a try soon.Kevin WhittenburgFirestudio 2626Mac OS X 10.6.8 and 10.9Logic Pro 9 and Logic Pro X, Cubase 7.58 core Mac Pro early 2009 - 20 GB RAM

I recently tried upgrading (on a separate drive) to Yosemite and it did indeed break my driver, so Mavericks is as far as I can go with this Interface. I'm in the market now for an apollo firewire quad and once that has been acquired I will rack my PreSonus 2626 interface and Digimax 8 channel mic pre's in a 24 channel to go package and use that for remote recording and just do overdubs and mixes in the studio. I rarely use more than 8 channels at one time in the studio anyway...